Identification of mercury-containing nanoparticles in the liver and muscle of cetaceans.

Natural mercury-containing nanoparticles (Hg-NPs) have been found in the environment, but the information for Hg-NPs in organisms was still limited. Clarifying the unique roles of Hg-NPs in organisms is crucial to fully understand the health risks of Hg. Herein, liver and muscle tissues of cetaceans were collected to identify the presence and characteristics of Hg-NPs. We found that methylmercury (MeHg) was the dominant species of Hg in muscles, while inorganic Hg (IHg) accounted for 84.4-99.0% (average 94.0%) of Hg in livers. By using transmission electron microscopy (TEM), size exclusion chromatography coupled with inductively coupled plasma mass spectrometry (SEC-ICPMS) and single particle ICPMS (sp-ICPMS), large amounts (9-161 µg/g) of Hg-NPs in livers and small amounts (0.1-0.4 µg/g) in muscles were observed, indicating that Hg-NPs was an important form of Hg in livers. Both small sized (5-40 nm) and large sized (>100 nm) Hg-NPs were identified, which were mainly complexed with selenium (Se) and sulfur (S) as well as a few cadmium (Cd), lead (Pb) and silver (Ag). This study provided direct evidence of Hg-NPs in marine mammals as well as their chemical form and size distribution, which are helpful for further understanding the biogeochemical cycle and health risk of Hg.

Development of a multifunctional gold nanoplatform for combined chemo-photothermal therapy against oral cancer.

Aim: To design and fabricate a multifunctional drug-delivery nanoplatform for oral cancer therapy. Materials & methods: Polyethylene glycol-stabilized, PDPN antibody (PDPN Ab)- and doxorubicin (DOX)-conjugated gold nanoparticles (AuNPs) were prepared and evaluated for their cytotoxicity and antitumor efficacy in both chemotherapy and photothermal therapy. Results: The obtained (PDPN Ab)-AuNP-DOX system presents low toxicity, a high drug loading capacity and cellular uptake efficiency. Both in vitro and in vivo experiments demonstrate that (PDPN Ab)-AuNP-DOX has enhanced antitumor efficacy. Treatment with (PDPN Ab)-AuNP-DOX combined with laser irradiation exhibits superior antitumor effects. Conclusion: This (PDPN Ab)-AuNP-DOX system may be used as a versatile drug-delivery nanoplatform for targeted and combined chemo-photothermal therapy against oral cancer.

Property-Activity Relationship of Black Phosphorus at the Nano-Bio Interface: From Molecules to Organisms.

As a novel member of the two-dimensional nanomaterial family, mono- or few-layer black phosphorus (BP) with direct bandgap and high charge carrier mobility is promising in many applications such as microelectronic devices, photoelectronic devices, energy technologies, and catalysis agents. Due to its benign elemental composition (phosphorus), large surface area, electronic/photonic performances, and chemical/biological activities, BP has also demonstrated a great potential in biomedical applications including biosensing, photothermal/photodynamic therapies, controlled drug releases, and antibacterial uses. The nature of the BP-bio interface is comprised of dynamic contacts between nanomaterials (NMs) and biological systems, where BP and the biological system interact. The physicochemical interactions at the nano-bio interface play a critical role in the biological effects of NMs. In this review, we discuss the interface in the context of BP as a nanomaterial and its unique physicochemical properties that may affect its biological effects. Herein, we comprehensively reviewed the recent studies on the interactions between BP and biomolecules, cells, and animals and summarized various cellular responses, inflammatory/immunological effects, as well as other biological outcomes of BP depending on its own physical properties, exposure routes, and biodistribution. In addition, we also discussed the environmental behaviors and potential risks on environmental organisms of BP. Based on accumulating knowledge on the BP-bio interfaces, this review also summarizes various safer-by-design strategies to change the physicochemical properties including chemical stability and nano-bio interactions, which are critical in tuning the biological behaviors of BP. The better understanding of the biological activity of BP at BP-bio interfaces and corresponding methods to overcome the challenges would promote its future exploration in terms of bringing this new nanomaterial to practical applications.

Cellular Uptake of Few-Layered Black Phosphorus and the Toxicity to an Aquatic Unicellular Organism.

With the potential continuous application of mono- or few-layered black phosphorus (BP) in electronic, photonic, therapeutic, and environmental fields, the possible side effects of BP on aquatic organisms after release into natural water are of great concern. We investigated the potential toxicity of BP on the unicellular organism, Tetrahymena thermophila. After the exposure for 8 h at 10 µg/mL, the reproduction of T. thermophila significantly decreased by 46.3%. Severe cell membrane and cilium damage were observed by scanning electron microscopy (SEM) upon treatment with BP. Based on bright-field microscopy and three-dimensional Raman imaging, we investigated the cellular uptake and translocation of BP within T. thermophila. It was observed that the engulfment of BP by T. thermophila was oral apparatus dependent, through which intracellular BP was then transported to the posterior end of T. thermophila by food vacuole packaging. Our study also revealed that BP induced the increase of intracellular reactive oxidant species and formed oxidative stress-dependent toxicity to T. thermophila. Our findings paved a way for better understanding the BP toxicityon aquatic organisms and its potential ecological risks.

Mutual detoxification of mercury and selenium in unicellular Tetrahymena.

Selenium (Se) is commonly recognized as a protective element with an antagonistic effect against mercury (Hg) toxicity. However, the mechanisms of this Hg-Se antagonism are complex and remain controversial. To gain insight into the Hg-Se antagonism, a type of unicellular eukaryotic protozoa (Tetrahymena malaccensis, T. malaccensis) was selected and individually or jointly exposed to two Hg and three Se species. We found that Se species showed different toxic effects on the proliferation of T. malaccensis with the toxicity following the order: selenite (Se(IV))>selenomethionine (SeMeth)>selenate (Se(VI)). The Hg-Se antagonism in Tetrahymena was observed because the joint toxicity significantly decreased under co-exposure to highly toxic dosages of Hg and Se versus individual toxicity. Unlike Se(IV) and Se(VI), non-toxic dosage of SeMeth significantly decreased the Hg toxicity, revealing the influence of the Se species and dosages on the Hg-Se antagonism. Unexpectedly, inorganic divalent Hg (Hg2+) and monomethylmercury (MeHg) also displayed detoxification towards extremely highly toxic dosages of Se, although their detoxifying efficiency was discrepant. These results suggested mutual Hg-Se detoxification in T. malaccensis, which was highly dependent on the dosages and species of both elements. As compared to other species, SeMeth and MeHg promoted the Hg-Se joint effects to a higher degree. Additionally, the Hg contents decreased for all the Hg-Se co-exposed groups, revealing a sequestering effect of Se towards Hg in T. malaccensis.

Improved Biocompatibility of Black Phosphorus Nanosheets by Chemical Modification.

Black phosphorus nanosheets (BPs) show great potential for various applications including biomedicine, thus their potential side effects and corresponding improvement strategy deserve investigation. Here, in vitro and in vivo biological effects of BPs with and without titanium sulfonate ligand (TiL4 ) modification are investigated. Compared to bare BPs, BPs with TiL4 modification (TiL4 @BPs) can efficiently escape from macrophages uptake, and reduce cytotoxicity and proinflammation. The corresponding mechanisms are also discussed. These findings may not only guide the applications of BPs, but also propose an efficient strategy to further improve the biocompatibility of BPs.

In vitro studies of a distillate of rectified essential oils on sinonasal components of mucociliary clearance.

BACKGROUND: Herbal remedies predate written history and continue to be used frequently for many common ailments. The essential oil mixture standardized is a phytopharmaceutical with a distillate of a mixture of rectified essential oils of eucalyptus, sweet orange, myrtle, and lemon as active ingredients used to treat respiratory diseases such as bronchitis and rhinosinusitis. We evaluated the pharmacologic effects of a distillate of rectified essential oils standardized on primary human upper respiratory epithelial cultures specifically addressing electrolyte transport, cilia beat frequency (CBF), airway surface liquid (ASL) hydration, and mucus transport velocity. METHODS: Well-differentiated primary human sinonasal epithelial cultures grown at an air-liquid interface were treated on the apical or basolateral surface with varying concentrations of a distillate of rectified essential oils standardized. Changes in CBF were determined using the Sissons-Ammons Video Analysis system while changes in chloride flux were determined using the fluorescent dye 6-methoxy-N-(3-sulfopropyl)quinolinium. ASL hydration was quantified using Texas red dextran and mucociliary transport velocity was measured using fluorescent microspheres and time lapse photography. RESULTS: When applied to the basolateral surface, a distillate of rectified essential oils standardized activated chloride efflux and ciliary beat in a dose-dependent fashion, increasing ASL height and accelerating mucociliary transport velocity. The ancillary apical application of a distillate of rectified essential oils standardized had minimal effects on the CBF. CONCLUSION: Basolateral application of a distillate of rectified essential oils standardized stimulates both chloride efflux and cilia beat frequency resulting in a synergistic effect dramatically augmenting mucociliary transport velocity. These in vitro data support the clinical efficacy of this phytopharmaceutical in respiratory inflammatory disorders.

Detection of trace levels of lead in aqueous liquids using extractive electrospray ionization tandem mass spectrometry.

A sensitive approach, based on semi-quantitative measurement of the characteristic fragments in multi-stage extractive electrospray ionization mass spectrometry (EESI-MS(n)), was developed for fast detection of trace levels of lead in aqueous liquids including mineral water, lake water, tap water, energy drinks, soft drinks, beer, orange juice, and tea. A disodium ethylene-diamine-tetraacetic acid (EDTA) aqueous solution was electrosprayed to produce negatively charged primary ions which then intersected the neutral sample plume to generate anions of EDTA-Pb(II) complexes. The charged EDTA-Pb(II) complexes were characterized with multistage collision induced dissociation (CID) experiments. The limit of detection (LOD) using EESI-MS(3) was estimated to be at the level of 10(-13)g/mL for directly detecting lead in many of these samples. The linear dynamic range was higher than 2 orders of magnitude. A single sample analysis could be completed within 2 min with reasonable semi-quantitative performance, e.g., relative standard deviations (RSDs) for deionized water were 4.6-7.6% during 5 experimental runs (each of them had 10 repeated measurements). Coca-cola and Huiyuan orange juice, representative beverage samples with complex matrices, generated recovery rates of 91.5% and 129%, respectively. Our experimental data demonstrated that EESI-MS is a useful tool for the fast detection of lead in various solutions, and EESI-MS showed promises for fast screening of lead-contaminated aqueous liquid samples.

[Simultaneous speciation of arsenic and selenium by high performance liquid chromatography-double channel atomic fluorescence spectrometry].

A comprehensive method for simultaneously detecting species of arsenic and selenium including arsenite (As(III)), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenate (As(V)), selenocystine (SeCys), selenomethionine (SeMet) and selenate (Se(IV)) was developed with high performance liquid chromatography-hydride generation-double channel atomic fluorescence spectrometry (HPLC-HG-AFS). An anion-exchange column (PRP-X100) with eluent of 10 mmol/L NH4H2PO4 containing 2.5% (v/v) methanol was employed to separate these species within 12 min. The detection limits of As(III), DMA, MMA, As(V), SeCys, SeMet and Se(IV) were 1, 3, 2, 3, 4, 18 and 3 microg/L (200 microL of injection), respectively. The relative standard deviations in five independent determinations varied from 1.9% to 6.1% for arsenic and selenium species at the concentration levels of 100 and 300 microg/L. The proposed method was applied to analyze the selenium yeast tablet and human urine samples. The recoveries from spiked selenium yeast tablet and urine samples ranged from 88% to 105% and from 83% to 108%, respectively. The results showed that this method can be used for determining arsenic and selenium species in urinary metabolites and drug samples in daily analysis conveniently.

Nasal saline irrigation facilitates control of allergic rhinitis by topical steroid in children.

OBJECTIVE: This study was designed to determine whether nasal saline irrigation improved the symptoms and signs of allergic rhinitis (AR) and whether nasal saline irrigation could be used as a complementary management of AR in children while less steroids were used. METHOD: 26 children with AR were divided into three groups and were given nasal saline irrigation and/or topical steroid. Symptoms and signs of AR and mucociliary clearance (MCC) were evaluated, and concentration of soluble intercellular adhesion molecule (sICAM)-1 in nasal secretion was detected. RESULTS: In AR children treated with nasal irrigation and tapered topical steroid at week 8 and week 12, a significant improvement in symptoms and signs was observed, and a significant decrease in the mean values of MCC and the mean concentrations of sICAM-1 in nasal secretions was also detected. CONCLUSION: Nasal saline irrigation can be viewed as a good adjunctive treatment option for AR. It permitted the use of less topical steroids for controlling AR in children, which will contribute to fewer side effects and less economic burden.

Interaction of methylmercury and selenium on the bioaccumulation and histopathology in medaka (Oryzias latipes).

Interaction of methylmercury and selenium in medaka (Oryzias latipes) on bioaccumulation of pollutants and histopathological changes in liver and gill were studied. Juvenile medaka fish were submitted to a series of waterborne methylmercury chloride (MMC), sodium selenite (Na(2)SeO(3)) and their mixture for 210 days, respectively. The methylmercury (MeHg) and selenium contents in the whole body of medaka were determined. The dose- and time-dependent increase of MeHg and selenium contents in medaka were observed. Histopathological changes, such as edema, vacuoles, pyknotic nucleus, and telangiectasis, could clearly be observed in the slices from the exposed medaka's liver and gill. Concurrent exposure to MMC and Na(2)SeO(3) showed the increased selenium accumulation. When the exposure molar ratio of MeHg:Se was about 1, the interaction between MeHg and selenium offered a limited protection against the serious intoxication of both MMC and Na(2)SeO(3) to medaka.

[Effects of irrigating solution of Sihuang on morphology and function of nasal mucosa following surgery for chronic sinusitis and nasal polyps].

OBJECTIVE: To investigate the effect of the irrigating solution of Sihuang (ISSH) given after endoscopic surgery for chronic sinusitis and nasal polyps. METHODS: ISSH was used to irrigate the operated sinus cavity for 4 weeks in 109 patients with chronic sinusitis and/or polyps treated by endoscopic surgery, and 0.9%; normal saline (NS) was given in the same manner in another 109 patients receiving ISSH for similar problems, and the effects of the irrigating solutions was compared. Before and 3 months after the surgery, respectively, 32 patients with sinusitis were selected from each group for saccharin test. The mucosa in the ostiomeatal complex region was examined by electron microscopy in 6 patients before, two weeks and one month after surgery, respectively. RESULTS: The total effective rate was not significantly different between the two groups, but the postoperative morphological and functional recovery of the nasal mucosa occurred earlier in ISSH than in NS group (P<0.05). The level of SIgA was similar between the two groups before treatment (P>0.05), whereas after ISSH treatment, the SIgA level was significantly elevated in the treated group. Mucociliary transport rate was similar between ISSH and NS groups before the surgery (3.14+/-1.05 mm/min vs 3.31+/-1.09 mm/min, P>0.05), but 3 month after the surgery, the mucociliary transport rate increased to 6.09+/-2.63 mm/min in ISSH group and 5.04+/-1.22 mm/min in NS group, showing significant difference between them. Under electron microscope, the cilia of the epithelial cells were found exfoliated preoperatively but regularly arranged after the surgery, presenting the "9+2" architecture of the microtubule. CONCLUSION: ISSH used after operation can improve the therapeutic effect of endoscopic surgery for chronic sinusitis and/or nasal polyps.